1. Field of the Invention
The present invention relates to device and method for transporting paper in photographic printers, or the like. More particularly, the invention is a photographic paper transporting device in which a single motor is used, in combination with pin-clutch mechanism, to feed photographic paper from a paper magazine and rewind the same.
2. Description of the Related Art
It is known to utilize a paper magazine containing a roll of photographic paper therein in light-tight fashion which is loaded in a photographic printer. The photographic paper is drawn out of the paper magazine and fed to an exposure station by means of a pair of feed rollers. The paper magazine is replaced when the size or surface type of the photographic paper is to be changed. In conventional photographic printers, a keyboard is operated to command a magazine change. Then, a paper transport system transports the photographic paper to locate the trailing end of the last exposed frame at a cutting position, so as to cut off any exposed portion of the photographic paper from unexposed portion. After printing, a winding shaft of the paper magazine is rotated by hand to wind the unexposed portion of the photographic paper back into the paper magazine.
Because of the need for manual rewinding, the conventional paper transport system is cumbersome. In view of this, Fuji Photo Film Co., Ltd. proposed a paper transport system for a photographic printer having a planetary gear-clutch mechanism for performing paper feeding and paper rewinding by means of a single motor (U.S. patent application No. 07/683,912).
In this type of paper transport system, the planetary gear-clutch mechanism is coupled to a paper feed gear train during paper feeding, so as to transmit forward rotation of the motor to a pair of feed rollers. The feed roller pair pulls photographic paper out of a paper magazine and transports it to an exposure station. When rewinding the photographic paper, the planetary gear-clutch mechanism is coupled to a paper rewinding gear train, so as to transmit reverse rotation of the motor to the paper magazine. Thereby, the paper roll in the paper magazine is rotated in a reverse direction so that the photographic paper is rewound onto the paper roll.
In such a paper transport system, teeth of the planetary gear-clutch mechanism may clash with each other, causing poor intermeshing. Furthermore, the gears may be applied with a force which urges the gears away from each other or too close to each other. The direction of such a force depends on the rotational direction of the gears. Therefore, change-over between paper feeding and paper rewinding cannot be performed in a stable manner.